Gliederung

Objective: We have successfully treated over two hundred high-grade glioma (HGG) patients with adjuvant immunotherapy consisting of vaccination with autologous dendritic cells (DC) loaded with autologous tumor lysate. It has recently been shown that regulatory T cells (Treg) play an important role in tumor immunology, counteracting anti-tumor immune responses. Up till now, the best marker for these Treg cells is a unique transcription factor, termed Foxp3. The aim of the present pilot study was (I) to check the correlation between low expression of the IL-7 receptor alpha subunit (CD127) and expression of Foxp3 on CD4+CD25+ Treg cells and (ii) to confirm the suppressive function of CD4+CD127dim cells.

Results: (I) CD127 surface staining showed two distinct populations of CD4+CD25+ cells: CD127dim expressing cells staining positive for the Treg marker Foxp3 and CD127+ cells staining negative for Foxp3. We found a significant positive correlation between Foxp3 expression and CD127dim expression in the CD4+CD25+ population. (ii) CD4+CD127dim cells were suppressive in an allogeneic MLR in concordance with Treg function.

Conclusions: These data confirm that CD127dim expression can be used as a marker of Treg cells in HGG patients. Compared to intracellular Foxp3 staining, CD127 surface staining is an easy way to monitor Treg cells and this will now be routinely used in the immune monitoring of HGG patients treated with autologous DC vaccination.